Air heater



Dec. 2 7, 1949 c. M. OSTERHELD AIR HEATER Filed July 27, 1946 IN VEN TOR. CLARK M. OSTERHELD Patented Dec. 27, 1949 j UNI-TED STATES PATENT OFFICE I AIR HEATER Clark M. Osterheld, Stoughton. Wis., assignor to McGraw Electric Company, Elgin, 111., a corporation of Delaware'- Application July 27, 1946, Serial No. 686,755

2 Claims. 1 a My invention relates to electric heaters and particularly to portable electric room and air heaters.

One object of my invention is to provide a novel metallic resistor member for a room heater. I Another object of my invention is to provide a novel support for the metallic resistor of a room heater.

Other objects of my invention will either be apparent from a description of one form of device embodying my invention or will be set forth in the course of such description and particularly in the appended claims.

In the drawings,

Figure 1 is a view mainly in front elevation with parts cut away of an electric room or air heater embodying my invention,

Fig. 2 is a transverse sectional view therethrough taken on the line 2-2 of Fig. 1,

Fig. 3 is a fragmentary, horizontal view thereof taken on the line 3-3 of Fig. 1, and

Fig. 4 is a cross-sectional View of a supporting means.

An electric air or roomheater H comprises a casing consisting of a rear wall I3 which is integral with a top wall or cover l5. The casing comprises further a front wall I! as well as a supporting means [9 which I may make of a suitable heat-resisting plastic such as Bakelite. The casing includes further side walls 2| and 23 and it is to be understood that the walls overlap in such manner as to form a pleasing appearance.

Within the casing I provide a plurality of electric heating units 25 here shown as four in number although I do not desire to be limited to such number since there is only a question of the amount of heat to be generated by the heating elements in my improved heater. Thus, for instance, the distance between the individual heaters 25 may be on the order of 3" to so that the width of the heater would vary from to 25".

I provide a pair of metallic rods 2! and 29, metallic rod 21 being supported by a bushing member 3| of electric-insulating material shown in section in Fig. 4 of the drawings, at each of its ends. The bushing members 3| are held by the side walls 2| and 23 as by individual capped nuts 33 or any other suitable holding means which may be of pleasing appearance.

Each of the heating units 25 comprises a pair of metal sheets 35 and 31 which may be held in proper operative and relatively closely adjacent positions relatively to each other so as to properly hold a resistor conductor 39 therebetween.

While I may make resistor conductor 39 of aluminum resistor material, I do not desire to be limited thereto since I may use any metallic resistor member now in use. While I have shown the resistance conductor 39 as comprising a strip I do not desire to be limited to the use of such strip since I may also use a round conductor wire. The resistance conductor 39 extends in zigzag shape from the upper rod 21 to the lower rod 29 and the distance between the individual zigzags as well as the height of the casing of the heater I I is made such that in combination with a resistance conductor of a given width and thickhess, will translate the desired amount of electrical energy into heat.

The nuts 4|, one on each side of the pairs of plates 35 and 31, are also used to eifect an electric conducting connection between the ends of the resistor 39 as by bending the resistance or a connector 43 around each of the rods 21 and 29.

Means for holding the metallic electric resistor conductor in the proper desired position between each pair of plates 35 and 31 may comprise a plurality of rivets 45 which extend through the two plates 35 and 31 at a number of spaced points particularly at or close to the side edges thereof. I

If desired, I may provide another heating unit adjacent to the front surface of the heater by providing a metal plate 41 which is spaced from the front plate I! by a resistor member 49, a plurality of rivets 5| being provided to hold plates I1 and 41 in tightly assembled positions relatively to each other. In case a relatively small width of electric air heater is made up, the resistance conductor 53 positioned between plates I! and 41 may extend entirely across the front surface of the heater, but I have shown each convolution of the resistor 53 as extending only across one-half of the total width of the front surface. The material as well as the shape of resistor 53 is the same as is resistor 39.

The material constituting the casing plates as well as the plates 35 and 31 and 41 may be, and preferably is, aluminum and, for example, I may mention that the thickness of a plate may be on the order of .035" to .06". While I may make all of these plates of aluminum, I do not desire to be limited thereto since other metals will respond in the desired manner to treatments hereinafter mentioned to provide an electric-insulating coating on the outside surface of said plates.

On the entire outer surface of the resistance conductors 39 and 53 I may provide a coating comprising an inorganic, integral, high-temperature-resisting, heat-conducting, as well as electric-insulating kind which may be generated on aluminum as by the use of the method set forth in Patent No. 1,526,127. I may also, or as an alternative, provide such a coating on either the inner surfaces of the respective plates Hand 31 or over their entire outer surface as well "as on either the inner surface of plates l1 and '41 although plate 41 may have its entire outer surface covered by such a coating. Generally speaking, the thickness of the coating is on the order of .001" and will withstand several thousand volts breakdown voltage. The temperature differential between the temperature of the resistor conductor and the outside surface of either of the plates 35 and 3'! or of plates 11 and 41 is on the order of 400 F.

The cover portion [5 may be provided with a plurality of slots 55 so as to permit of an upward now of heated air from the bottom or the heater through the heater, past the heating elements and upwardly "and outwardly. Rear plate l3 may beheld in proper operative position relatively to support 1 9 as by a plurality of short screws 51.

I provide a pan 59 which may be "secured to a portion '61 of base member l9 so as to permit of pulling out the pan 59 for the purpose 'of filling it with water. Means for supporting pan 59 com"- Lprises a-she'et'or a plurality 'of bars 63 interfitting with base 1'9.

The air heater embodying my invention thus provides an electric air heater having a totally encased resistor member in which the heat is transmitted to the metal plates and is radiated by these plates to the air.

While 'I may provide an electric-insulating coating on only the outer surface or the resistor 01' on the resistor-engaging surface of the metal plates, I may also provide such coating on both the resistor and the entire outer surface of the metal clamping plates.

Various modifications may be made in the device embodying my invention without departing from the spirit or scope thereof, and all such modifications coming clearly within the scope or the appended claims shall be considered as part of my invention.

I claim as my invention:

1. An electric air heater comprising a substantially rectangular casing, a plurality of spaced metal rods within said casing and supported thereby, a plurality of metallic resistor members, pairs of thin rectangular sheet metal members mounted on said rods and supporting said resistor members, means for clamping each pair of sheet metal members together for supporting a resistor member between them, and an insulating layer between each resistor member and its supporting "sheet member comprising an integral, inorganic, high-temperature-resisting, heatcon'ducting, electric-insulating coating on one of said member's.

2. An electric heater comprising a substantially rectangular casing, a pair of spaced metal rods within said casing and. supported thereby, a pluraiity of spaced pairs or thin plates mounted on said rods, a resistor member between the plates of each pair, said resistor extending in 'ii'g 'zag sh-ape between said rods and having its ends electrically connected to said rods, and means for clamping each pair of plates against the resisters thereb'etween, the material of "said plates and resistors including aluminum, said plates and resistors having thereon an integral, inorganic, heat-conducting, nigh-temperature-re- 's' 'istin'g electrically insulating coating which includes an oxidation product of aluminum.

M. SST-ERHEID.

REFERENCES CI-TED The following references 'are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 768,764 Leonard Aug. '30, 1 904 791,691 Hadaway, Jr. June 6, I905 1,305,532 Fulton June 3, 1919 1,593,753 "Spackman Sept. '1, 1926 ,6r0,1-1 6 Woods et a1 Dec. *1, 1926 2,357,2 3 Ricard Sept. 5, 1m 2,360,265 Osterheld Oct. 1'0, 1944 

